ST662A DC-DC CONVERTER FROM 5V TO 12V, 0.03A FOR FLASH MEMORY PROGRAMMING SUPPLY ■ ■ ■ ■ ■ ■ OUTPUT VOLTAGE: 12V ± 5% SUPPLY VOLTAGE RANGE: 4.5V TO 5.5V GUARANTEED OUTPUT CURRENT UP TO 30mA VERY LOW QUIESCENT CURRENT: 100mA LOGIC CONTROLLED ELECTRONIC SHUTDOWN: 1µA JUST CAPACITORS NEEDED (NO INDUCTOR) DESCRIPTION The ST662A is a regulated charge pump DC-DC converter. It provides 12V ± 5% output voltage to program byte-wide flash memory, and can supply 30mA output current from input as low as 4.75V. A logic controlled shut down pin that interfaces directly with microprocessor reduces the supply current to only 1µA. DIP-8 SO-8 TYPICAL APPLICATION CIRCUIT April 2004 1/13 ST662A ABSOLUTE MAXIMUM RATINGS Symbol VCC SHDN IO Parameter DC Input Voltage to GND Shutdown Voltage Output Current Continuous Ptot Power Dissipation Top Operating Ambient Temperature Range(for AC SERIES) (for AB SERIES) Storage Temperature Range Tstg Value Unit -0.3 to 6 V -0.3 to VCC+0.3 50 mA V 500 mW -0 to 70 -40 to 85 °C -40 to 150 °C Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is not implied. THERMAL DATA Symbol Rthj-case Parameter Thermal Resistance Junction-case SO-8 Unit 20 °C/W CONNECTION DIAGRAM (top view) ORDERING CODES TYPE DIP-8 SO-8 (*) ST662AB ST662AC ST662ABN ST662ACN ST662ABD ST662ACD (*) AVAILABLE IN TAPE & REEL WITH "-TR" SUFFIX. PIN DESCRIPTION PIN N° Symbol 1 2 3 4 5 C1C1+ C2C2+ VCC Negative Terminal For The First Charge Pump Capacitor Positive Terminal For The First Charge Pump Capacitor Negative Terminal For The Second Charge Pump Capacitor Positive Terminal For The Second Charge Pump Capacitor Supply Voltage 6 VOUT 12V Output Voltage VOUT= VCC When in Shutdown Mode 7 8 GND SHDN Ground Active High C-MOS logic level Shutdown Input. SHDN is internally pulled up to VCC. Connect to GND for Normal Operation. In Shutdown mode the charge pumps are turned off and VOUT= VCC 2/13 Name and Function ST662A ELECTRICAL CHARACTERISTICS (refer to the test circuits, VCC = 4.5V to 5.5V, TA = TMIN to TMAX,unless otherwise specified. Typical Value are referred at TA = 25°C) Symbol VO Parameter Output Voltage Test Conditions Min. Typ. IO = 0 to 20 mA 11.4 IO = 0 to 30 mA, VCC = 4.75 to 5.5 V 11.4 NO LOAD, VSHDN = 0 Max. Unit 12 12.6 V 12 12.6 100 500 1 10 µA -12 -5 µA IQ1 Quiescent Current IQ2 Shutdown Current NO LOAD, VSHDN = VCC ISH Shutdown Pin Current VSHDN = 0, VCC = 5V VIL Shutdown Input Low Threshold VIH Shutdown Input High Threshold fO Oscillator Frequency VCC = 5 V, IO = 30 mA 400 Power Efficiency VCC = 5 V, IO = 30 mA 72 VCC - VOUT Switch Impedance VSHDN = VCC = 5V, IO = 100 µA -50 VSHDN = VCC = 5V ν RSW 0 µA µA 0.4 V 2.4 V 1 KHz % 2 KΩ Figure 1 : Output Voltage vs Temperature Figure 3 : Supply Current vs Temperature Figure 2 : Output Voltage vs Temperature Figure 4 : Supply Current vs Supply Voltage 3/13 ST662A Figure 5 : SHDN Pin Current vs Temperature Figure 7 : Output Voltage vs Shutdown Input Voltage Figure 6 : Output Voltage vs Shutdown Input Voltage Figure 8 : Output Voltage vs Shutdown Input Voltage Figure 9 : Test Circuit 4/13 ST662A DESCRIPTION The ST662 is an IC developed to provide a 12V regulated output 30mA from voltage input as low as 4.75 without any inductors. It is useful for a wide range of applications and its performances makes it ideal for flash memory programming supply. An evaluation kit is provided to facilitate the application. This include a single-side demo board designed for surface-mount components.The operating principle of ST662 (see fig. 10) is to charge C1 and C2 capacitor by closing the S1 switch (while S2 is opened) at the VCC voltage. After S1 will be opened and S2 closed so that C1 and C2 capacitors are placed in series one to each other, and both are in series with VIN. The sum of VC1 and VC2 and VI is applied to the capacitor C4. This works as voltage triple. An amplifier error checks the output voltage and blocks the oscillator if the output voltage is greater than 12V. The shutdown pin is internally pulled to VCC. When it is held low the output voltage rises to +12V. Fig.11 shows the transition time of the shut down pin when the VSHDN goes from 5V to 0V. Input logic levels of this input are CMOS compatible Applying a logic high at this input, the VOUT oscillator will be blocked and the VOUT will reach the VI value by D1. In this condition ICC will be. low as 1µA. The fig.12 shows the transition time of the shut down pin when the VSHDN goes from 0V to 5V. Figure 10 : Operating Principle Circuit Figure 11 : Exiting Shutdown Figure 12 : Entering Shutdown NOTE: VCC = 5 V, IOUT = 200 µA NOTE: VCC = 5 V, IOUT = 200 µA 5/13 ST662A APPLICATION CIRCUIT Based on fast charge/discharge of capacitors, this circuit involves high di/dt values limited only by RON of switches. This implies a critical layout design due to the need to minimize inductive paths and place capacitors as close as possible to the device. A good layout design is strongly recommended for noise reason. For best performance, use very short connections to the capacitors and the values shown in table 1. C3 and C4 must have low ESR in order to minimize the output ripple. Their values can be reduced to 2µF and 1µF, respectively, when using ceramic capacitors, but must be of 10µF or larger if aluminium electrolytic are chosen. C5 must be placed as close to the device as possible and could be omitted if very low output noise performance are not required. Fig 13 and Fig 14 show, respectively, our EVALUATION kit layout and the relatively. Figure 13 : KIT Lay-out Figure 14 : Electrical Schematic 6/13 ST662A TABLE 1: List of Components CAPACITOR TYPE VALUE (µF) Charge Pump C1 Charge Pump C1 Input C3 Output C4 Decoupling C5 Ceramic Ceramic Electrolytic Tantalum Electrolytic Tantalum Ceramic 0.22 0.22 4.7 4.7 0.1 ST662A OUTPUT PERFORMANCE Figure 15 : Output Voltage vs Output Current Figure 17 : Load Transient Response NOTE: VCC = 5 V, IOUT = 0 to 30mA Figure 16 : Efficiency vs Output Current Figure 18 : Load Transient Response NOTE: VCC = 4.5 to 5.5V, I OUT = 30 mA 7/13 ST662A HOW TO INCREASE OUTPUT CURRENT OR OUTPUT VOLTAGE CAPABILITY Current capability is limited by RON of internal switches. It is possible to increase it connecting in parallel two or more ST662A devices; each one of them can supply 30mA. The figure 19 shows the electric schematic. The capacitors C3, C4 and C5 must be placed very close to the ICs on the board. If this is not possible, you can place two different capacitors, each of them of half value, very close to the respective integrated circuit. Fig. 21 show the Output Current capability of the proposed circuit. If an output voltage greater than 12V is required, it’s possible to realize the circuit of the following diagram (figure 20). The relevant Output Current capability is shown in figure 22 in which is shown the output voltage vs load current. Figure 19 : Application Circuit for Two ST662A in Parallel TABLE 2: List of Components 8/13 CAPACITOR TYPE VALUE (µF) C1A C2A C1B C2B C3 C4 C5 Ceramic Ceramic Ceramic Ceramic Electrolytic Tantalum Electrolytic Tantalum Ceramic 0.22 0.22 0.22 0.22 10 10 0.22 ST662A Figure 20 : Application Circuit for Output Voltage greater than 12V Figure 21 : Output Voltage for the Application with Two Device in Parallel Figure 22 : Output Voltage for Application with Output Voltage greater than 12V 9/13 ST662A Plastic DIP-8 MECHANICAL DATA mm. inch DIM. MIN. A TYP MAX. MIN. 3.3 TYP. MAX. 0.130 a1 0.7 B 1.39 1.65 0.055 0.065 B1 0.91 1.04 0.036 0.041 b b1 0.028 0.5 0.38 0.020 0.5 D 0.015 0.020 9.8 0.386 E 8.8 0.346 e 2.54 0.100 e3 7.62 0.300 e4 7.62 0.300 F 7.1 0.280 I 4.8 0.189 L Z 3.3 0.44 0.130 1.6 0.017 0.063 P001F 10/13 ST662A SO-8 MECHANICAL DATA DIM. mm. MIN. TYP inch MAX. MIN. TYP. MAX. A 1.35 1.75 0.053 0.069 A1 0.10 0.25 0.04 0.010 A2 1.10 1.65 0.043 0.065 B 0.33 0.51 0.013 0.020 C 0.19 0.25 0.007 0.010 D 4.80 5.00 0.189 0.197 E 3.80 4.00 0.150 0.157 e 1.27 0.050 H 5.80 6.20 0.228 0.244 h 0.25 0.50 0.010 0.020 L 0.40 1.27 0.016 0.050 k ddd 8˚ (max.) 0.1 0.04 0016023/C 11/13 ST662A Tape & Reel SO-8 MECHANICAL DATA mm. inch DIM. MIN. A MAX. MIN. 330 13.2 TYP. MAX. 12.992 C 12.8 D 20.2 0.795 N 60 2.362 T 12/13 TYP 0.504 22.4 0.519 0.882 Ao 8.1 8.5 0.319 0.335 Bo 5.5 5.9 0.216 0.232 Ko 2.1 2.3 0.082 0.090 Po 3.9 4.1 0.153 0.161 P 7.9 8.1 0.311 0.319 ST662A Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. 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